Table of contents:

Chimney renovation: you should know that
Chimney renovation: you should know that

Chimney renovation is often straightforward and quick. How you can finance the costs with a subsidy, why stainless steel is not always the best solution and when you better do the work yourself: DAS HAUS provides tips.

Table of contents Table of contents Chimney renovation: when is it useful and how much does it cost?

  • When is chimney renovation necessary?
  • Chimney renovation: Instructions for planning and implementation
  • Chimney renovation in practice
  • Chimney renovation: stainless steel, ceramic or plastic?
  • What does a chimney renovation cost?
  • The tip for bargain hunters: KfW funding

Table of contents Table of contents Chimney renovation: when is it useful and how much does it cost?

  • When is chimney renovation necessary?
  • Chimney renovation: Instructions for planning and implementation
  • Chimney renovation in practice
  • Chimney renovation: stainless steel, ceramic or plastic?
  • What does a chimney renovation cost?
  • The tip for bargain hunters: KfW funding

When the fireplace is on strike, it is usually time for a chimney renovation. Excessive smoke formation and unpleasant smells are the first signs of a need for action. But modernizing the heating system often requires additional intervention. The old chimney is usually given a smaller pipe system made of stainless steel. Plastic and ceramics are also popular. Chimney refurbishment becomes necessary if exhaust gases condense too low in the chimney and penetrate the masonry. However, homeowners like to do simple work themselves. Finished kits are particularly practical because they come with instructions for assembly. Costs and time expenditure are also manageable.

When is chimney renovation necessary?

There are various reasons why renovating the chimney is sensible or absolutely necessary. The chimney sweep is often the first to recognize this. But homeowners also have to check their chimney regularly and pay attention to the relevant information. Because the chimney sweep handicraft law has been in effect since 2013, which allows homeowners to choose a provider for the maintenance of the chimney, at the same time the owners are obliged to ensure that regular inspection is carried out. Those who comply with this generally avoid expensive follow-up costs.

1. Chimney damage and sooting

Stress cracks and crumbling joints are often the first signs of necessary construction work. Homeowners should also keep an eye on increased lichen formation and plant growth. Anyone who is a little talented in craftsmanship can make improvements themselves. It becomes more difficult with sooting. When water, tar and acids move into the walls, yellow-brown spots appear. In addition, an unpleasant smell spreads. With strong sooting, the risk of fire increases and even the statics are at risk.

2. Soot burn and soot formation

In the case of stubborn soot formation - for example due to insufficient chimney cleaning - or a soot fire, remediation is necessary. You should therefore always follow the instructions and care instructions that you received from your chimney sweep or heating engineer, for example.

3. Asbestos in the fireplace

Chimneys built between 1960 and 1990 often contain asbestos. Homeowners who fear asbestos in the chimney should get help from experts. In this case, chimney renovation must be carried out with special care, since the chimney often remains.

4. Modernization of the heating system

A new heating system often also requires chimney renovation. Old fireplaces are rarely suitable for lower exhaust gas temperatures and do not lead them all the way to the top. The result: exhaust gases already condense down in the shaft and in the worst case lead to sooting or collapse of the chimney. In addition, the cross section of many chimneys is too large for the lower amount of exhaust gas from modern combustion plants.

Chimney renovation: Instructions for planning and implementation

As a rule, your chimney sweep will be able to tell you whether renovation is necessary. If you are planning a new heating system, a good heating engineer may also offer a suitable system. Every chimney renovation has its own challenges. Therefore, there is no general guide that is suitable for all fireplaces. However, you should note the following:

  1. Make sure that the fireplace needs to be renovated.
  2. Calculate the dimensions of the required pipes, taking into account all slopes and the cross-section over the entire length of the chimney. Alternatively, a service provider can do this.
  3. Report construction measures to the responsible chimney sweep at least ten days before the start of the renovation.
  4. Finished kits make chimney renovation easier. You can get these from stationary retailers and online.
  5. The assembly instructions for kits can often already be found online. This way you can find out in advance and assess whether you can do the work yourself.
  6. Experts in the specialist trade will advise you on which special tools you need for a fireplace renovation.
  7. Always take appropriate security measures.
  8. Store the material carefully.
  9. Not only do you clean the fireplace, but also check the statics beforehand.
  10. After the renovation, the chimney sweep is used for acceptance.

The chimney sweep can tell you whether a chimney is in need of renovation. If you carry out the renovation on your own, he will check it after completion.

Photo: fotolia / krizz7

Chimney renovation in practice

In the simplest case, the chimney runs straight, so that the pipe system is lowered from the roof into the old chimney. However, the heater and stove must be connected to the pipe system. This requires some chiseling work. A fireplace renovation usually takes one to two days. You can do the renovation yourself with skilled craftsmanship and a specially designed kit. Flexible systems made of plastic or iron are particularly suitable for this. However, you should have experience with the chisel work or consult experts. This makes assembly easier.

Chimney renovation: stainless steel, ceramic or plastic?

Which material you need for a fireplace renovation depends on which fuel and which heating system you use. The flexibility of the pipes is just as important. Is there offset? How high can the weight be? Should the material be particularly durable and sustainable? And of course the costs also play a role.

1. Stainless steel: the classic for chimney renovation

If you rely on stainless steel, you can hardly go wrong. It is basically suitable for all heating technologies and fuels. Flexible tubes make it easier to use with angled chimneys. The low weight is also a big advantage. Stainless steel is also often used for exterior installation on the facade. In addition, stainless steel pipes quickly reach operating temperature. This promotes a good draft in the shaft.

Chimney renovation with stainless steel has one disadvantage, however: the pipes are only partially corrosion-resistant. Anyone who saves on quality here pays for it quickly. If you still want to use stainless steel pipes, you should invest in a more corrosion-resistant stainless steel for acidic exhaust gases.

2. Plastic: The lightweight for difficult renovations

Plastic pipes are suitable for oil or gas condensing boilers. They are particularly flexible in terms of guidance, are easy to assemble and are relatively inexpensive. Plastic pipes for stoves are not suitable. Compared to stainless steel and ceramics, however, plastic wears out the fastest. Therefore, you should most likely expect follow-up costs here. However, if a chimney is particularly angled or there are problems with the statics, plastic is often the first choice for chimney renovation.

3. Ceramics: sustainable chimney renovation

If you want to be flexible in the long term, you should consider ceramic pipes when refurbishing your chimney. They are equally suitable for high and low temperatures, are particularly sustainable and acid-resistant. A later change of fuel or heating technology is particularly easy with ceramics. It is durable and even a soot fire doesn't bother her. So the best choice? Sometimes. In addition to higher costs, ceramics have another major disadvantage: changes in direction in the course of the chimney require the prying of walls and some angles ceramics do not even take part. Additional heat insulation is also required when heating solid fuels.

What does a chimney renovation cost?

Basically, the costs of a chimney renovation depend on the material used and the installation costs. It is particularly cheap with stainless steel. It is available from around 60 euros per meter. Plastic is also cheap. Ceramic, on the other hand, is a lot more expensive. On average, you should plan between 1, 000 and 2, 000 euros for a ten-meter-high chimney. Is the fireplace difficult to access? Is there offset? Was asbestos used? This makes renovating the chimney more expensive. In contrast, kits not only make work easier, they also make it cheaper. It is best to have several offers from different companies. Remember to write your requirements as precisely as possible so that there are no unexpected extra costs.

The tip for bargain hunters: KfW funding

Better not save on material or crafts costs. If possible, use KfW funding instead. If you as a home owner modernize your heating system, you are probably also entitled to grants for chimney renovation. However, you must apply for this in good time before starting work.

Anja Schmidt

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